Method for concentrating waste sulfuric acid by utilizing waste heat of titanium dioxide calcinator

A titanium dioxide and roasting furnace technology, applied in the direction of manganese sulfate, magnesium sulfate, iron sulfate, etc., can solve the problems of frequent scaling cleaning, increasing the diameter of graphite tube heat exchangers, and high energy consumption for cooling and heating processes. Achieve significant social and environmental benefits, reduce equipment investment and operating costs, and achieve high device production efficiency

Inactive Publication Date: 2013-02-06
黄正源
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of these methods are: 1) using the rotary kiln exhaust gas in one stage of concentration, only paying attention to the utilization of heat, and ignoring the economic value of titanium dioxide in the exhaust gas; 2) the titanium dioxide dust brought out from the rotary kiln exhaust gas, It has a certain solubility in acid, and the unhydrolyzed titanyl sulfate remaining in the acid not only causes the viscosity of the acid to increase, but also brings more trouble to the subsequent evaporation and concentration; 3) it is used in the second-stage concentration The block type graphite heat exchanger is not conducive to the heat exchange of titanium dioxide waste acid containing scaling substances and a large amount of solid phase precipitates, and the cleaning of scaling is relatively frequent, which is costly and time-consuming; 4) in the third stage A silicon carbide evaporator is used in the concentration to further heat and concentrate the waste acid that has been concentrated to 70% to 80%, which not only requires a large investment in equipment, but also consumes a lot of energy for cooling and heating of the process.
In order to solve the above problems, the Chinese patent application "Prevent scaling method and special device of one-effect heating equipment for the conc

Method used

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  • Method for concentrating waste sulfuric acid by utilizing waste heat of titanium dioxide calcinator
  • Method for concentrating waste sulfuric acid by utilizing waste heat of titanium dioxide calcinator
  • Method for concentrating waste sulfuric acid by utilizing waste heat of titanium dioxide calcinator

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] 1) Under normal temperature and pressure and stirring (60r / min), add 300g of anhydrous sodium sulfate to 1000g of titanium white waste acid containing about 20% sulfuric acid, continue stirring for 30min, let the suspension cool to room temperature, and separate the solid and liquid Na 2 SO 4 10H 2 O crystallization; Gained filtrate was added 250g of anhydrous sodium sulfate under normal temperature and pressure and under stirring, continued to stir for 30min, allowed the suspension to be cooled to normal temperature, and the solid-liquid separation went out Na 2 SO 4 10H 2 O crystallization. The second filtrate was cooled to -5°C while stirring, and kept stirring at this temperature for 30 minutes to allow the FeSO 4 ·7H 2 Inorganic salts such as O are fully crystallized and precipitated. Then solid-liquid separation to obtain FeSO 4 ·7H 2 O and other inorganic salt crystallization and filtrate. The mass percent concentration of sulfuric acid in the filtrate ...

Embodiment 2

[0046] 1) Under normal temperature and pressure and stirring (80r / min), add 500g of anhydrous ferrous sulfate to 1000g of titanium white waste acid containing about 25% sulfuric acid, continue stirring for 30min, let the suspension cool to room temperature, and separate the solid and liquid FeSO 4 ·7H 2 O crystallization; the obtained filtrate was added with 300 g of anhydrous ferrous sulfate under stirring at normal temperature and pressure, and continued to stir for 30 minutes, allowing the suspension to cool to normal temperature, and the solid-liquid separation of FeSO 4 ·7H 2 O crystallization; the obtained secondary filtrate was added with 200 g of anhydrous ferrous sulfate at normal temperature and pressure under stirring, and continued to stir for 30 min, allowing the suspension to cool to normal temperature, and the solid-liquid separation of FeSO 4 ·7H 2 O crystallization; three filtrates were cooled to 10°C with stirring, and kept stirring at this temperature for...

Embodiment 3

[0049] 1) Under normal temperature and pressure and stirring (80r / min), add 600g ferrous sulfate monohydrate to 1000g titanium white waste acid containing about 23% sulfuric acid, continue stirring for 30min, let the suspension cool to room temperature, and separate the solid and liquid FeSO 4 ·7H 2 O crystallization; Gained filtrate adds 500g ferrous sulfate monohydrate again under the same condition as above, stirs, separates; Gained secondary filtrate adds 400g ferrous sulfate monohydrate again at normal temperature and pressure and under stirring, continues stirring, is cooled to normal temperature , Separation of FeSO 4 ·7H 2 O crystallization; three filtrates were cooled to 10°C with stirring, and kept stirring at this temperature for 30min, allowing FeSO 4 ·7H 2 Inorganic salts such as O are fully crystallized and precipitated. Then solid-liquid separation. The mass percent concentration of sulfuric acid in the filtrate is 64.2%, which is sent to the acid hydrolys...

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Abstract

The invention discloses a method for concentrating waste sulfuric acid by utilizing waste heat of a titanium dioxide calcinator, comprising the following steps: at normal temperature and pressure, proper amount of water absorbent is added to titanium dioxide waste acid, liquid water is dissolved out in the form of solid crystal water through the water absorbent, filtrate after solid-liquid separation is cooled, iron vitriol in the solution is crystallized and dissolved out, and the acid liquid is further concentrated; the two steps are repeatedly carried out until the concentration of sulfuric acid in the final filtrate reaches more than 60%, and then the final filtrate is utilized in the acid hydrolysis procedure; and the water absorbent is dehydrated and dried to be regenerated by taking dustproof tail gas of the calcinator, and the steam generated in the drying and regeneration is cooled and flows back to technological process as washing water in titanic acid rinsing or is drained. The method provided by the invention solves the problems of more equipment, long flow and easy blockage in the existing technology, and the equipment investment and operating cost are reduced; and the water absorbent is recycled after being regenerated, so that the energy is saved, the consumption is reduced, and the efficiency is obvious; no wastewater, waste gases and residues are generated in the whole technology, the operability is strong, the productivity of equipment is high, the flow is simple, the investment is less, the cost is low, energy is saved, emission is reduced, and the benefit is obvious.

Description

technical field [0001] The invention relates to a method for concentrating waste sulfuric acid by utilizing waste heat of a titanium dioxide roasting furnace. Background technique [0002] The production of titanium dioxide by the sulfuric acid method has the advantages of sufficient raw material sources and low cost, but every ton of titanium dioxide produced will produce about 6-8 tons of waste acid containing 20% ​​sulfuric acid. If the waste acid is not recycled, it will inevitably cause The waste of a large number of precious resources, improper handling will also cause secondary pollution and damage to the environment. [0003] At present, the treatment methods of titanium dioxide waste sulfuric acid mainly include the following: [0004] ① Directly return to the production line for diluting concentrated sulfuric acid. The advantage is that it can be reused directly without adding too much treatment and transportation equipment, but because the discharge of waste aci...

Claims

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Application Information

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IPC IPC(8): C01B17/88C01G49/14C01G45/10C01F5/40C01D5/18
CPCY02P20/129
Inventor 黄正源
Owner 黄正源
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